In engineering installations power is frequently transmitted from a source, such as an internal combustion engine, a gas turbine or an electric motor, to a receiver, such as a compressor, dynamo, propellor or wheel, through a gearbox by means of torque applied to a rotating shaft. The transmission of torque is therefore of primary importance in the research and development of more efficient and reliable transmission systems. Design engineers are concerned to provide a steady transmission of torque through transmission systems so as to minimize gear wear, bearing and coupling failure, shaft fatigue failure and other associated torsional vibration and noise problems. Modern power transmission systems, furthermore, often involve the use of flexible couplings, the lifetimes of which are severely restricted if high levels of fluctuating torque are present.
To date, progress in these fields has been hindered by the lack of an instrument capable of providing immediate, accurate measurements of time-resolved torque through a driven system.